1. Field
The present disclosure relates to a non-contact charging system.
2. Description of the Related Art
A known non-contact charging system charges, for example, an electric vehicle in a non-contact manner by utilizing a physical phenomenon such as electromagnetic induction. Such a system needs to adjust the positional relationship between a device that transmits electric power (hereinafter referred to as a transmitter) and a device that receives the electric power (hereinafter referred to as a receiver) appropriately before a charging operation is performed.
As illustrated in FIG. 10A, suppose a transmitter 2 on the ground 1 transmits electric power, and a receiver 4 in a vehicle 3 and a receiver 6 in a vehicle 5 receive the electric power. Here, the vehicles 3 and 5 belong to different vehicle size classes, and a gap G2 between the transmitter 2 and the receiver 6 is larger than a gap G1 between the transmitter 2 and the receiver 4. As shown in FIG. 10B, electric power transmission efficiency tends to decrease as the three-dimensional positional displacement (in horizontal and vertical directions) between the transmitter and the receiver increases. In the graph, the solid line represents the transmission efficiency of the vehicle 3 (the gap G1), and the broken line represents the transmission efficiency of the vehicle 5 (the gap G2).
Japanese Unexamined Patent Application Publication No. 2013-021886 (paragraphs [0044]-[0048] and FIG. 6) proposes a charging device that adjusts the three-dimensional positions of a transmitter and a receiver by configuring a relay device for relaying electric power such that the relay device can move in a horizontal, vertical, or rotational direction.